Breakdown voltage requirements for semiconductor devices may range from a few volts to over 10,000 volts, depending upon the particular application. Typically, this voltage is supported by depletion layers formed across p-n junctions, metal semiconductor interfaces (e.g., Schottky diodes), and metal-oxide semiconductor (MOS) interfaces.
The inventors hereof have recognized that it would be desirable to minimize device resistance while maintaining breakdown voltage capability that is as close as possible to the intrinsic capability of the underlying semiconductor material. In practice, however, premature voltage breakdown due to the occurrence of high electric fields at the edges of the device can limit resistance vs. breakdown voltage performance. Some of the edge termination techniques previously used to alleviate the electric field crowding at the edges of the device include moat etch, surface implantation, single floating guard rings, bevel edge, and field plate terminations.